[Critical review of anti-influenza drugs]

Neuraminidase inhibitors such as zanamivir and oseltamivir belong to a new class of antiviral drugs for the treatment and prevention of influenza. As yet however, the therapeutic efficacy of these drugs (shortening of recovery time by approximately one day) has only been demonstrated in healthy adults affected by influenza A, but not in risk groups and in influenza B disease, whereas studies of prophylactic efficacy are still going on. Neither do these drugs impact on viral spread, a public health risk against which the economic advantages of early work resumption have to be weighed. Since flu symptoms can be caused by other germs than the influenza A or B virus, caution in prescribing these drugs seems warranted, also to prevent the development of drug resistance. In addition, when designing therapeutic efficacy trials in risk groups, selecting the rate of secondary complications and death may be more adequate as clinical endpoint than (economically important) duration of illness.